Aigile · AI Coding Agent Architectures

Claude Code

Anthropic

graph TD U([User]) --> CM[CLAUDE.md
always loaded] U --> SC[Slash Commands
.claude/commands/] CM --> CTX[Session Context] SC --> CTX CTX --> SK[Skills
.claude/skills/
auto-loaded by model] CTX --> TASK[Task Tool
native primitive] TASK --> SA[Subagents
.claude/agents/
isolated context] TASK --> AT[Agent Teams
experimental
TeamCreate/TaskCreate
SendMessage] SA --> H[Hooks
settings.json
Pre/PostToolUse
Stop/SessionStart] AT --> H H --> MCP[MCP Servers
external tools
GitHub/DBs/APIs] SK --> PL[Plugins
bundle all above
marketplace] SA --> PL H --> PL MCP --> PL CTX --> LSP[LSP Servers
code intelligence
rust-analyzer/pyright] CTX --> OT[OTel Telemetry
native OTLP/Prometheus
Grafana/Datadog] style U fill:#f7ece8,stroke:#c84b2f,color:#1a1a1a style CM fill:#fdf6e3,stroke:#b08a2e,color:#1a1a1a style SC fill:#fdf6e3,stroke:#b08a2e,color:#1a1a1a style CTX fill:#f5f2eb,stroke:#d4cfc2,color:#1a1a1a style SK fill:#eef7f1,stroke:#2d7a4f,color:#1a1a1a style TASK fill:#c84b2f,stroke:#c84b2f,color:#faf8f3 style SA fill:#eef7f1,stroke:#2d7a4f,color:#1a1a1a style AT fill:#fdf6e3,stroke:#b08a2e,color:#1a1a1a style H fill:#eef7f1,stroke:#2d7a4f,color:#1a1a1a style MCP fill:#f5f2eb,stroke:#d4cfc2,color:#7a7468 style PL fill:#f5f2eb,stroke:#d4cfc2,color:#7a7468 style LSP fill:#f5f2eb,stroke:#d4cfc2,color:#7a7468 style OT fill:#eef7f1,stroke:#2d7a4f,color:#1a1a1a

CLAUDE.md Slash Commands Task Tool Subagents 12+ Hook Events Skills MCP OTel Telemetry LSP Plugins Agent Teams TaskCreate/Update SendMessage TeamCreate/Delete

Most mature agent ecosystem. Task tool is the native spawning primitive — subagents and Agent Teams both sit on top of it. Hooks fire at 12+ lifecycle events. OTel telemetry is native, not bolted on. Agent Teams (experimental) adds a shared task board on disk + peer-to-peer agent messaging — unique to Claude Code.

GitHub Copilot

GitHub / Microsoft

graph TD U([User]) --> CI[copilot-instructions.md
always loaded] U --> PR[Prompt Files
.github/prompts/
user slash commands] CI --> CTX[Session Context] PR --> CTX CTX --> INS[Instructions
.github/instructions/
file-pattern scoped] CTX --> AG[Custom Agents
.github/agents/
subagent invocation] CTX --> SK[Skills
.github/skills/
auto or /name] AG --> H[Hooks
hooks.json
PostToolUse/Stop
requires opt-in] SK --> H CTX --> MCP[MCP Servers
external tools] CTX --> PL[Plugins
bundle agents/skills/hooks] CTX --> CCA[Coding Agent
async GitHub Actions
PR workflow] style U fill:#edf2fb,stroke:#2a5fa5,color:#1a1a1a style CI fill:#edf2fb,stroke:#2a5fa5,color:#1a1a1a style PR fill:#edf2fb,stroke:#2a5fa5,color:#1a1a1a style CTX fill:#f5f2eb,stroke:#d4cfc2,color:#1a1a1a style INS fill:#eef7f1,stroke:#2d7a4f,color:#1a1a1a style AG fill:#eef7f1,stroke:#2d7a4f,color:#1a1a1a style SK fill:#eef7f1,stroke:#2d7a4f,color:#1a1a1a style H fill:#fdf6e3,stroke:#b08a2e,color:#1a1a1a style MCP fill:#f5f2eb,stroke:#d4cfc2,color:#7a7468 style PL fill:#f5f2eb,stroke:#d4cfc2,color:#7a7468 style CCA fill:#eef7f1,stroke:#2d7a4f,color:#1a1a1a

copilot-instructions.md Prompt Files Custom Agents Instructions Skills (open std) MCP Plugins Coding Agent (async) Hooks (opt-in) No Task Tool No TaskCreate/Update No Agent Teams No SendMessage No OTel Telemetry

Strongest in VS Code integration and async PR workflow via Coding Agent. Custom agents work as subagents (one level deep). Hooks exist but require chat.hooks.enabled=true — off by default. No shared task board or peer messaging between agents. Multi-agent orchestration is sequential only — plan documents act as the task board in practice.

Codex CLI

OpenAI

graph TD U([User]) --> AM[AGENTS.md
global + per-directory
cascade override] U --> PR[Prompts
~/.codex/prompts/
reusable templates] AM --> CTX[Session Context
272K token window] PR --> CTX CTX --> SK[Skills
.agents/skills/
SKILL.md open std] CTX --> CFG[config.toml
agent roles
model per role] CFG --> SA[Sub-agents
max 6 concurrent
handoff pattern] SA --> H[Hooks
AfterAgent
AfterToolUse
nascent system] CTX --> MCP[MCP Servers
codex mcp
experimental] CTX --> SB[OS Sandbox
Seatbelt/Landlock
kernel-level] CTX --> CLD[Codex Cloud
async cloud tasks
worktree isolation] SA --> OAI[Agents SDK
external orchestration
Project Manager pattern] style U fill:#eef7f1,stroke:#2d7a4f,color:#1a1a1a style AM fill:#eef7f1,stroke:#2d7a4f,color:#1a1a1a style PR fill:#eef7f1,stroke:#2d7a4f,color:#1a1a1a style CTX fill:#f5f2eb,stroke:#d4cfc2,color:#1a1a1a style SK fill:#eef7f1,stroke:#2d7a4f,color:#1a1a1a style CFG fill:#eef7f1,stroke:#2d7a4f,color:#1a1a1a style SA fill:#fdf6e3,stroke:#b08a2e,color:#1a1a1a style H fill:#fdf6e3,stroke:#b08a2e,color:#1a1a1a style MCP fill:#fdf6e3,stroke:#b08a2e,color:#1a1a1a style SB fill:#eef7f1,stroke:#2d7a4f,color:#1a1a1a style CLD fill:#eef7f1,stroke:#2d7a4f,color:#1a1a1a style OAI fill:#f5f2eb,stroke:#d4cfc2,color:#7a7468

AGENTS.md cascade Prompt templates Skills (open std) config.toml roles OS Sandbox Codex Cloud 400K token window Sub-agents (max 6) Hooks (2 events only) MCP Multi-agent (Agents SDK) No shared task board No SendMessage No native OTel

Strongest in sandboxing (OS-level Seatbelt/Landlock) and cloud task delegation. AGENTS.md cascades from global → project → subdirectory, providing fine-grained context. Multi-agent orchestration requires the external Agents SDK — not native to the CLI. Hooks are nascent (2 events vs Claude Code's 12+). Skills follow the same open standard as Claude Code and Copilot.

Feature Comparison

✓ Native / Built-in ~ Experimental / Partial ↗ External / SDK required ✗ Not available

Feature	Claude Code	GitHub Copilot	Codex CLI
Ambient memory file	✓ CLAUDE.md	✓ copilot-instructions.md	✓ AGENTS.md cascade
User slash commands	✓ .claude/commands/	✓ .github/prompts/	~ ~/.codex/prompts/
Custom agents / roles	✓ .claude/agents/	✓ .github/agents/	✓ config.toml roles
Skills (open standard)	✓ .claude/skills/	✓ .github/skills/	✓ .agents/skills/
Hooks — lifecycle events	✓ 12+ events	~ opt-in, 3 events	~ 2 events (nascent)
MCP servers	✓ native	✓ native	~ experimental
Plugins / marketplace	✓ native	✓ native	✗ not available
Agent spawning primitive	✓ Task tool	~ subagent invocation	~ sub-agents (max 6)
Parallel agent execution	✓ run_in_background	✗ sequential only	~ experimental
Shared task board	~ TaskCreate/Update (exp)	✗ plan doc only	✗ not available
Agent-to-agent messaging	~ SendMessage (exp)	✗ not available	✗ not available
Agent memory persistence	✓ memory: field	✗ not available	✗ not available
OTel / native telemetry	✓ OTLP/Prometheus	✗ session logs only	✗ not available
LSP code intelligence	✓ native plugins	✓ native (VS Code)	✗ not available
OS-level sandboxing	✗ permission model only	✗ GitHub Actions env	✓ Seatbelt/Landlock
Async cloud execution	✗ local only	✓ Coding Agent / PR workflow	✓ Codex Cloud
Multi-agent orchestration	~ Agent Teams (exp)	✗ sequential subagents	~ Agents SDK (external)